TW200426749A - Power supply for an LCD panel - Google Patents

Power supply for an LCD panel Download PDF

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Publication number
TW200426749A
TW200426749A TW093109968A TW93109968A TW200426749A TW 200426749 A TW200426749 A TW 200426749A TW 093109968 A TW093109968 A TW 093109968A TW 93109968 A TW93109968 A TW 93109968A TW 200426749 A TW200426749 A TW 200426749A
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TW
Taiwan
Prior art keywords
voltage
power supply
signal
supply system
patent application
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TW093109968A
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Chinese (zh)
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TWI242177B (en
Inventor
Yung-Lin Lin
Da Liu
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O2Micro Inc
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Publication of TW200426749A publication Critical patent/TW200426749A/en
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Publication of TWI242177B publication Critical patent/TWI242177B/en

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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
    • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
    • H05B41/282—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
    • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
    • H05B41/282—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices
    • H05B41/2825—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices by means of a bridge converter in the final stage
    • H05B41/2827—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices by means of a bridge converter in the final stage using specially adapted components in the load circuit, e.g. feed-back transformers, piezoelectric transformers; using specially adapted load circuit configurations
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
    • H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
    • H05B41/282—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices
    • H05B41/2825—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices by means of a bridge converter in the final stage
    • H05B41/2828—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices by means of a bridge converter in the final stage using control circuits for the switching elements
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/36—Controlling
    • H05B41/38—Controlling the intensity of light
    • H05B41/39—Controlling the intensity of light continuously
    • H05B41/392—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor
    • H05B41/3921—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor with possibility of light intensity variations
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Circuit Arrangements For Discharge Lamps (AREA)
  • Inverter Devices (AREA)

Abstract

A power supply system is provided for a multiple lamp LCD panel. In one aspect, the power supply includes a plurality of transformers for driving a plurality of respective CCFLs. The primary sides of each transformer are coupled in series to thereby reduce the stress on each transformer. For LCD panels that include longer CCFLs, a power supply is provided that includes a plurality of transformers for driving a plurality of respective CCFLs. The primary sides of each transformer are coupled in series and each lamp is coupled to two secondary sides of the transformers, thereby reducing the problems associated with longer CCFL tubes. In any of the embodiments, the power supply can be adapted to convert a high voltage DC signal to high voltage AC used to power the lamps.

Description

200426749 (1) 玖、發明說明 【發明所屬之技術領域】 本發明係有關一種用於液晶顯示器（LCD )的電源， 更具體的是有關一種給液晶電視機（LCDTV )的多數冷陰 極螢光燈供電的背光電源。 【先前技術】 第1圖所示爲一種液晶顯示器（LCD )螢幕的習用電 源系統10。在該習用系統中，1 10V/220V交流電源通過 一個整流器電路或功率因數校正（PFC )電路12轉換爲 一個高直流電壓。然後，該高直流電壓通過一個直流/直 流（DC/DC)轉換器14降壓後，可以爲一些電子裝置提 供例如 5 V和1 2 V的低電壓，這些電子裝置包括微控制 器、記憶體、TFT驅動器、顯示卡和冷陰極螢光燈 (CCFLs )。換流器（inverter ) 16再把低直流電壓轉換 爲一個高交流電壓從而給LCD螢幕18的CCFL供電。直 流/直流轉換器1 4和直流/交流換流器1 6的多次電壓轉換 會影響轉換效率並在系統中產生熱量。對於大 LCD螢 幕，比如LCD電視中的螢幕，大部分的電能都消耗在 C C F L上。因此，提高用於C C F L的換流器的效率就很重 要。 第2圖所示爲一種提高換流器系統效率的習用電源系 統 2 0，其中，高直流電壓直接送入直流/交流換流器 1 6 ’。這減少了直流/直流轉換器的中間步驟，從而提高了 -4- (2) (2)200426749 總效率。 如第3圖、第3 A圖和第4圖所示，一個高直流電壓 轉換爲一個交流信號需要一個低匝數比的變壓器接到 CCFL。第3圖所示爲一種換流器電路30，該換流器電路 3 0建立在一個半橋式電路（兩個開關）上，並且包括一 個換流器控制器32，該換流器控制器32驅動開關34和 3 6給變壓器3 8提供必需的電壓。換流器控制器3 2和半 橋式電路都是本領域所公知的。第3 A圖所示爲一種 Class D式換流器電路 30’，第4圖所示爲一種全橋式 (四個開關）換流器電路3 0”，它們都是本領域所公知 的。第4圖所示電路還示出了回授線，但回授線在本論述 中不予討論。因爲變壓器的尺寸是根據CCFL的應用情況 來選擇的，所以驅動CCFL的二次線圈通常是由負載需求 所固定的。然而，在高電壓輸入的情況下，變壓器的一次 線圈的線圈匝數遠高於爲低電壓輸入（譬如5V-20V )所 驅動的線圈匝數，這就增加了變壓器的複雜度和成本。 【發明內容】 本發明的主要目的，係提出了一種用於LCD螢幕的 電源系統，包括： 一個能控制多數開關，從而把一個直流信號轉換爲〜 個高電壓交流信號的換流器控制器； 多數接收高電壓交流信號的變壓器，並且上述每個變 壓器都產生一個高電壓正弦信號，其中每個變壓器都有〜 -5- (3) (3)200426749 個一次側和一個二次側，每個一次側相互串聯在該高電壓 交流信號兩端；和 一個包括多數冷陰極螢光燈管的LCD螢幕，每個燈 管都由上述變壓器一個對應二次側供電。 本發明之另一目的，亦提出了一種用於LCD螢幕的 電源系統，包括： 一個能控制多數開關，從而把一個直流信號轉換爲一 個高電壓交流信號的換流器控制器； 多個接收高電壓交流信號的變壓器，並且上述每個變 壓器都產生一個高電壓正弦信號，其中每個變壓器都有一 個一次側和一個二次側，其中每個一次側相互串聯在該高 電壓交流信號兩端；和 一個包括多數冷陰極螢光燈管的LCD螢幕，每個燈 管都由上述變壓器至少兩個對應二次線圈供電。 這裏給出的任何實施例中’電源都可以從一個高直流 電壓信號轉換爲一個用來給諸燈管供電的高交流電壓° 値得本領域的技術人員重視的是’雖然下面的具體實 施方式的詳細說明’是基於本發明之技術特徵所提出0勺車交 佳實施例，但是本發明並不僅僅局限於這些實施例°反 而，本發明涉及範圍廣泛’其範圍僅由相應串請專利範匱1 限定。 本發明的其他特徵和優點將在下面的具體實施方式中 得到充分體現，具體實施方式中請參照附*圖及其相關資 料、元件標號。 -6- (4) (4)200426749 【實施方式】 在液晶電視中，通常都採用多數CCFL來給LCD螢 幕提供充足亮度，例如，取決LCD螢幕的尺寸大小，而 有4至32個CCFL。一方面，本發明在電源轉換過程中， 變壓器的一次線圈是相互串聯的。 第5圖所示爲本發明的一個用於LCD螢幕的換流器 W路5 0的示範性實施例。在本示範性實施例中，變壓器 T I和T2的一次側串聯在一起。因此，每個一次側上的線 圈電壓爲跨在整個線圈上的輸入電壓的一半。與第4圖的 _壓器一次線圈相比，本方法能使線圈匝數減少爲原來的 ~半。在第5圖所示的半橋式電路中，把變壓器的一次側 相串聯，這使得每個線圈上的電壓減小爲輸入電壓的四分 &〜。當應用半橋式電路時，每個線圈上的電壓應力爲輸 入電壓的1/(2N)(其中N爲串聯的變壓器的個數）。當 然’第5圖所示電路中也可以改用一個全橋式電路，此時， 當N個變壓器的一次線圈相串聯時，每個一次線圈上的 電壓應力減小爲輸入電壓的1 /N。第5 A圖所示爲一個 C1 a s s d換流器電路，因爲變壓器的一次線圈也是相串聯 的，所以它與上述第5圖所示的電路具有相同的優點。 第6圖所示爲本發明換流器電路中的變壓器和L C D 螢幕的電路圖5 2。在該圖中，此槪念延伸至藉由於第5 圖所示的A點和B點之間，串聯連接四個一次側τ 1、 T2、丁3、和T4，來給四個CCFL燈管供電。同樣，利用 (5) (5)200426749 類似方法延伸至第7圖中的N燈管電路5 2 ’ ，其用N個 變壓器給N個c C F L燈管供電。 因爲每個一次線圈相串聯，所以在開關電路（例如， 半橋式、全橋式或Class D式的開關電路）導通、斷開期 間’流經每個變壓器一次側的電流是相同的。第5圖、第 6圖和第7圖中，開關電路連在a點和b點之間。這種結 構解決了習用技術的缺點並進一步達到每個驅動C C F L的 變壓器一次側的電流平衡的功效。 第8圖所示爲本發明的一種示範性LCD電源系統1 00 的詳細電路圖。該電源包括一個驅動半橋式電路中的兩個 開關5 4和5 6的換流器控制器5 2，如上述第5圖所示。 該換流器控制器5 2包括用來控制連在電路上C C F L供電 狀況的電壓和電流回授。根據上述的原理和描述，每個 CCFL由如圖所示的一個一次側串聯變壓器所供電（例 如，ΤΙ，T2…T ( η-1 ) ，Τη， Τχ ;其中η代表偶數個 燈管，X代表奇數個燈管）。 電流回授是由圖8電路中的燈管1 ( C C F L 1 )和燈 管2 ( CCFL 1 )導出的回授電路60產生的。該示範性電 流回授電路60包括一個光耦合器62和一個調節器64。 調節器64放大電流回授信號CFB，光耦合器62再把回授 信號傳送給換流器控制器52。同樣，電壓回授資訊也是 由電壓回授電路7 〇產生的。該示範性實施例中，從電路 中每個燈管所偵測到的電壓回授資訊產生一個電壓回授信 號 V f b。 -8- (6) (6)200426749 第8圖所示的詳細電路中還包括其他與本發明有關的 電路。例如，一個脈寬調變（p w Μ )控制器5 8產生直流 電源信號（例如’ 1 2 V和5 V )給其他與L C D顯示器相關 的元件（例如記億體、微處理器等）供電。同樣，如上所 述’功率因數校正（P F C )電路1 2可以採用任何傳統和/ 或自定義的電路來產生一個高直流電壓。 另一方面，本發明亦提出了一種驅動長C C F L 燈管的電路。L C D電視中採用的c C F L燈管的尺寸通常比 攜帶型裝置中的LCD顯示器的CCFL燈管長。而驅動長 C C F L變得更困難。例如，如第3圖、第3 a圖和第4圖 所示之驅動任何長約6 0釐米以上燈管的習用方法中，需 要在CCFL上加一個高頻高電壓（通常在1〇〇〇伏有效値 左右），而C C F L的另一側電位接近於底盤接地（c h a s s i s ground)。由於CCFL和底盤接地之間存在泄流路徑，所 以這些驅動方法通常會使CCFL燈管的一側變黑。長燈管 可表示75至80 cm或更長，並且長燈管通常意味著有一 個洩漏電容，從而影響燈管電極之間的電子漂移。 爲了解決該問題，本發明提出了 一種不同於習用技術 而進一步改良的驅動技術。如第9圖所示，一根長燈管可 以由兩個相位極性相反的變壓器驅動。第9圖中，CCFL 1 由T1二次線圈的正極和T2二次線圈的負極驅動（正負 極是由變壓器產生的正弦電源信號的半個週期表示的）。 實際上，C C F L 1的中心爲近似零電位。例如’每個變壓器 輸出5 0 0伏有效値時’其電壓應力和機械間距就安全要求 (7) (7)200426749 範圍而言就會減小很多。 另一方面，上述驅動技術也可以改進爲如第1 0圖所 示。第10圖所示爲一種用兩個控制器202和204與兩個 換流器電路2 0 6和 2 0 8來驅動一個 C C F L的驅動電路 2 0 0。兩個換流器電路通過一個同步信號2 1 0彼此相連’ 因此控制器2 0 2、2 0 4控制各自的換流器電路2 0 6、2 0 8 ’ 從而產生如圖1 〇中所示近似1 8 0度相位差的正弦信號。 這確保燈管能在每半個週期接收到來自每個換流器的全部 電壓，而不存在電源信號抵消。當然，本電路還可以包括 電壓和/或電流回授，來控制燈管的供電狀況。 本發明的換流器控制器可以是包括用來調節傳送至燈 管功率的減光電路（例如，脈衝模式、類比式和/或相位 式）的習用換流器控制器。能控制半橋式、全橋式、 Class D式和/或其他換流器電路的換流器控制器都是本領 域所公知，並且都與本發明等同。例如，在此引作參考的 美國專利Ν〇·6,2 5 9,6 1 5和Ν〇·5,6 1 5,093都分別披露了用 於全橋式和半橋式換流器電路的換流器控制器。換流器控 制器還可以採用由〇2MiCr〇國際有限公司生產的，例如No. OZ960、OZ961、OZ965、OZ970、OZ971、OZ972 或 OZ9RR。 另外，在本發明的揭露與說明下本領域之技術人員可 以了解到，如圖所示的L C D螢幕包括能產生一個表示燈 管負載上電壓和/或電流情況的電壓和/或電流回授信號的 電路。在此所述的換流器控制器還能接收該回授資訊，從 -10- (8) (8)200426749 而調節供給燈管負載上的電壓和/或電流。在前述的示範 性實施例中，電流回授可以是第5圖和第5A圖中的兩個 燈管中的一個產生的，或者第6圖、第7圖和第8圖中的 N個燈管中的兩個燈管產生。第9圖中，電流回授控制信 號是由未與燈管相連的變壓器二次線圈部分產生的，在該 情況下，流至燈管電流的每半個週期都得到監控。同樣， 電壓回授控制信號可以由本領域熟知的方法產生。 在示範性實施例中，通過換流器控制器的控制使得變 壓器和電源相連。該換流器控制器把一個高電壓直流信號 源轉換爲一個局電壓交流信號（方波）。接著，變壓器把 高電壓交流信號轉換爲高電壓正弦電源給燈管供電。當 然，本發明也可以用一個低電壓直流電源，此時變壓器將 把電壓提高到一個適當的電壓來驅動燈管。本領域的技術 人員將知道許多對本發明的改進，所有的這些改進都認爲 是在本發明的精神之內，都受限於本發明的申請專利範 圍0 【圖式簡單說明】 第1圖所示爲一種用於LCD螢幕的習用電源系統方 塊圖； 第2圖所不爲另一種用於L C D螢幕的習用電源系統 方塊圖； 弟3圖所不爲一種用於LCD營幕的習用換流器電路 圖； -11 - (9) (9)200426749 第3A圖所示爲另一種用於LCD螢幕的習用換流器電 路圖； 第4圖所示爲另一種用於LCD螢幕的習用換流器電 路圖； 第5圖所示爲本發明的用於L C D螢幕的換流器電路 的一個示範性實施例； 第5A圖所示爲本發明的用於LCD螢幕的換流器電路 的另一個示範性實施例； 第6圖所示爲本發明的換流器電路中的變壓器和l C D 螢幕的一電路圖； 第7圖所示爲本發明的換流器電路的中變壓器和LCD 螢幕的另一電路圖； 第8圖所示爲本發明的LCD電源系統的詳細電路 圖； 第9圖所示爲本發明的換流器電路中的變壓器和L C D 螢幕的另一電路圖；和 第10圖所示爲另一種一個CCFL用兩個控制器和兩 個換流器電路驅動的驅動電路。 【主要元件符號說明】 ]0、2 0、1 0 0 電源系統 12 功率因數校正電路 14 轉換器 ]6’、16 直流/交流換流器 -12- (10) (10)200426749 18 液晶顯示器螢幕 30、30，、30”、50、50，、206、2 08 換流器電路 3 2、5 2、5 2，、2 0 2、2 0 4 換流器控制器 34、 36、 54、 56 開關 38 變壓器 60 該示範性電流回授電路 62 光耦合器 64 調節器 2 0 0驅動電路 2 1 0同步信號 -13-200426749 (1) Description of the invention [Technical field to which the invention belongs] The present invention relates to a power supply for a liquid crystal display (LCD), and more specifically to a cold cathode fluorescent lamp for a liquid crystal television (LCDTV). Powered backlight power. [Prior Art] FIG. 1 shows a conventional power supply system 10 for a liquid crystal display (LCD) screen. In this conventional system, a 10V / 220V AC power source is converted into a high DC voltage by a rectifier circuit or a power factor correction (PFC) circuit 12. Then, after the high DC voltage is stepped down by a DC / DC converter 14, low voltages such as 5 V and 12 V can be provided for some electronic devices, such as a microcontroller, a memory , TFT driver, graphics card and cold cathode fluorescent lamps (CCFLs). The inverter 16 converts the low DC voltage into a high AC voltage to power the CCFL of the LCD screen 18. Multiple voltage conversions of the DC / DC converter 14 and the DC / AC converter 16 will affect the conversion efficiency and generate heat in the system. For large LCD screens, such as those in LCD TVs, most of the power is consumed by CCFL. Therefore, it is important to improve the efficiency of the inverter for C C F L. Fig. 2 shows a conventional power supply system 20 for improving the efficiency of a converter system, in which a high DC voltage is directly sent to a DC / AC converter 16 '. This reduces the intermediate steps of the DC / DC converter, which improves the overall efficiency of -4- (2) (2) 200426749. As shown in Figure 3, Figure 3A, and Figure 4, converting a high DC voltage to an AC signal requires a low turns ratio transformer connected to the CCFL. FIG. 3 shows an inverter circuit 30, which is built on a half-bridge circuit (two switches) and includes an inverter controller 32, the inverter controller The 32 drive switches 34 and 36 provide the necessary voltage to the transformer 38. Inverter controller 32 and half-bridge circuits are well known in the art. Figure 3A shows a Class D-type inverter circuit 30 ', and Figure 4 shows a full-bridge (four-switch) converter circuit 30 ", which are all well known in the art. The circuit shown in Figure 4 also shows the feedback line, but the feedback line will not be discussed in this discussion. Because the size of the transformer is selected according to the application of the CCFL, the secondary coil driving the CCFL is usually composed of The load demand is fixed. However, in the case of high voltage input, the number of turns of the primary coil of the transformer is much higher than the number of turns driven by the low voltage input (such as 5V-20V), which increases the transformer's Complexity and cost. [Summary of the invention] The main purpose of the present invention is to propose a power supply system for an LCD screen, which includes: a switch that can control most switches, thereby converting a DC signal into ~ high voltage AC signals Current controller; most of the transformers that receive high-voltage AC signals, and each of the above-mentioned transformers produces a high-voltage sinusoidal signal, each of which has ~ -5- (3) (3) 200426749 once And a secondary side, each primary side being connected in series with each other at both ends of the high-voltage AC signal; and an LCD screen including most cold cathode fluorescent lamp tubes, each of which is powered by a corresponding secondary side of the transformer. Another object of the present invention is to provide a power supply system for an LCD screen, including: an inverter controller capable of controlling most switches to convert a DC signal into a high-voltage AC signal; Transformers for voltage AC signals, and each of the above-mentioned transformers generates a high-voltage sinusoidal signal, wherein each transformer has a primary side and a secondary side, and each primary side is connected in series with each other at both ends of the high-voltage AC signal; And an LCD screen that includes most cold-cathode fluorescent tubes, each tube is powered by at least two corresponding secondary coils of the above transformer. In any of the embodiments given here, the 'power source can be converted from a high DC voltage signal For a high AC voltage used to power the lamps, those skilled in the art value The detailed description of the specific embodiment is a “carrying cart” embodiment based on the technical characteristics of the present invention, but the present invention is not limited to these embodiments. Instead, the present invention covers a wide range. Please limit the scope of patent scope 1. Other features and advantages of the present invention will be fully reflected in the following specific implementations, please refer to the attached drawings and related materials, component numbers in specific implementations. -6- (4) ( 4) 200426749 [Embodiment] In LCD TVs, most CCFLs are usually used to provide sufficient brightness to the LCD screen, for example, depending on the size of the LCD screen, there are 4 to 32 CCFLs. On the one hand, the invention In the process, the primary coils of the transformer are connected in series with each other. FIG. 5 shows an exemplary embodiment of a converter W circuit 50 for an LCD screen according to the present invention. In the present exemplary embodiment, the primary sides of the transformers T I and T2 are connected in series. Therefore, the coil voltage on each primary side is half the input voltage across the entire coil. Compared with the primary coil of Fig. 4, the method can reduce the number of coil turns to the original ~ half. In the half-bridge circuit shown in Figure 5, the primary side of the transformer is connected in series, which reduces the voltage on each coil to a quarter of the input voltage & ~. When a half-bridge circuit is used, the voltage stress on each coil is 1 / (2N) of the input voltage (where N is the number of transformers in series). Of course, a full-bridge circuit can also be used in the circuit shown in Figure 5. At this time, when the primary coils of N transformers are connected in series, the voltage stress on each primary coil is reduced to 1 / N of the input voltage. . Figure 5A shows a C1 a s s d converter circuit. Because the primary coil of the transformer is also connected in series, it has the same advantages as the circuit shown in Figure 5 above. Fig. 6 shows the circuit diagram of the transformer and the LCD screen in the inverter circuit of the present invention. In this figure, this idea extends to four CCFL lamps by connecting four primary sides τ 1, T2, D3, and T4 in series between points A and B shown in Figure 5. powered by. Similarly, (5) (5) 200426749 is similarly used to extend to the N tube circuit 5 2 ′ in FIG. 7, which uses N transformers to power N c C F L tubes. Because each primary coil is connected in series, the current flowing through the primary side of each transformer is the same during the switching circuit (eg, half-bridge, full-bridge, or Class D-type switching circuit) on and off. In Figures 5, 6 and 7, the switch circuit is connected between points a and b. This structure solves the shortcomings of conventional techniques and further achieves the effect of current balancing on the primary side of each transformer driving CCFL. FIG. 8 is a detailed circuit diagram of an exemplary LCD power supply system 100 according to the present invention. The power supply includes an inverter controller 52 which drives two switches 54 and 56 in a half-bridge circuit, as shown in Fig. 5 above. The inverter controller 52 includes voltage and current feedback for controlling the power supply condition of the CCFL connected to the circuit. According to the above principles and descriptions, each CCFL is powered by a primary-side series transformer as shown in the figure (for example, Ti, T2 ... T (η-1), Tη, Tχ; where η represents an even number of lamps, X Represents an odd number of lamps). The current feedback is generated by the feedback circuit 60 derived from the lamp 1 (CCFL 1) and the lamp 2 (CCFL1) in the circuit of FIG. The exemplary current feedback circuit 60 includes an optocoupler 62 and a regulator 64. The regulator 64 amplifies the current feedback signal CFB, and the photocoupler 62 transmits the feedback signal to the inverter controller 52. Similarly, the voltage feedback information is also generated by the voltage feedback circuit 70. In this exemplary embodiment, a voltage feedback signal V f b is generated from the voltage feedback information detected by each lamp in the circuit. -8- (6) (6) 200426749 The detailed circuit shown in Fig. 8 includes other circuits related to the present invention. For example, a pulse width modulation (pwM) controller 58 generates a DC power supply signal (e.g., '12 V and 5 V) to power other components related to the LCD display (e.g., terabyte, microprocessor, etc.). Also, as described above, the 'power factor correction (PFC) circuit 12 can use any conventional and / or custom circuit to generate a high DC voltage. On the other hand, the invention also proposes a circuit for driving a long C C F L lamp. The size of the c C F L tube used in the L C D TV is generally longer than the CCFL tube of an LCD display in a portable device. It becomes more difficult to drive long C C F L. For example, as shown in Figures 3, 3a, and 4, the conventional method of driving any lamp tube longer than 60 cm in length requires a high frequency and high voltage (usually 1,000) to be applied to the CCFL. The voltage on the other side of the CCFL is close to the chassis ground. Due to the leakage path between the CCFL and chassis ground, these drive methods usually blacken one side of the CCFL tube. A long tube can represent 75 to 80 cm or longer, and a long tube usually means a leakage capacitance that affects the electronic drift between the tube electrodes. In order to solve this problem, the present invention proposes a driving technology which is further improved from the conventional technology. As shown in Figure 9, a long lamp can be driven by two transformers with opposite phase polarity. In Figure 9, CCFL 1 is driven by the positive pole of the T1 secondary coil and the negative pole of the T2 secondary coil (the positive and negative poles are represented by a half cycle of the sinusoidal power signal generated by the transformer). In fact, the center of C C F L 1 is approximately zero potential. For example, “the output voltage of each transformer is 500 volts effective hours”, the voltage stress and the mechanical distance will be greatly reduced in terms of the range of safety requirements (7) (7) 200426749. On the other hand, the above driving technology can also be improved as shown in FIG. 10. Figure 10 shows a drive circuit 2 0 0 that uses two controllers 202 and 204 and two inverter circuits 206 and 208 to drive a C C F L. The two converter circuits are connected to each other through a synchronization signal 2 1 0 '. Therefore, the controllers 20 2 and 2 0 4 control the respective converter circuits 2 6 and 2 0 8' to generate the same as shown in FIG. 10 A sinusoidal signal with a phase difference of approximately 180 degrees. This ensures that the lamp can receive the full voltage from each inverter every half cycle without the power signal cancellation. Of course, the circuit can also include voltage and / or current feedback to control the power supply of the lamp. The inverter controller of the present invention may be a conventional inverter controller including a dimming circuit (for example, a pulse mode, an analog type, and / or a phase type) for adjusting the power delivered to the lamp. Converter controllers capable of controlling half-bridge, full-bridge, Class D and / or other converter circuits are well known in the art and are all equivalent to the present invention. For example, U.S. Pat. Nos. 6,2 5 9,6 1 5 and No. 5,6 1 5,093, both incorporated herein by reference, disclose switching for full-bridge and half-bridge converter circuits, respectively. Flow controller. The inverter controller can also be produced by 02MiCrO International Co., Ltd., such as No. OZ960, OZ961, OZ965, OZ970, OZ971, OZ972 or OZ9RR. In addition, under the disclosure and description of the present invention, those skilled in the art can understand that the LCD screen shown in the figure includes a voltage and / or current feedback signal capable of generating a voltage and / or current condition on the lamp load. Circuit. The inverter controller described herein can also receive the feedback information and adjust the voltage and / or current supplied to the load of the lamp from -10- (8) (8) 200426749. In the foregoing exemplary embodiment, the current feedback may be generated by one of the two lamps in FIGS. 5 and 5A, or the N lamps in FIGS. 6, 7, and 8 Two lamps in the tube are produced. In Figure 9, the current feedback control signal is generated by the secondary coil portion of the transformer that is not connected to the lamp. In this case, every half cycle of the current flowing to the lamp is monitored. Also, the voltage feedback control signal can be generated by methods well known in the art. In an exemplary embodiment, the transformer is connected to a power source through the control of a converter controller. The converter controller converts a high voltage DC signal source into a local voltage AC signal (square wave). The transformer then converts the high-voltage AC signal into a high-voltage sinusoidal power source to power the lamp. Of course, the present invention can also use a low voltage DC power supply, in which case the transformer will increase the voltage to a suitable voltage to drive the lamp. Those skilled in the art will know many improvements to the present invention, all of which are considered to be within the spirit of the present invention and are limited by the scope of patent application of the present invention. [Simplified description of the drawings] Figure 1 Shown is a block diagram of a conventional power system for LCD screens; Figure 2 is not a block diagram of another conventional power system for LCD screens; Figure 3 is not a conventional converter for LCD screens Circuit diagram; -11-(9) (9) 200426749 Figure 3A shows a circuit diagram of another conventional inverter for LCD screen; Figure 4 shows a circuit diagram of another conventional inverter for LCD screen; FIG. 5 illustrates an exemplary embodiment of an inverter circuit for an LCD screen according to the present invention; FIG. 5A illustrates another exemplary embodiment of an inverter circuit for an LCD screen according to the present invention; Figure 6 shows a circuit diagram of a transformer and a CD screen in a converter circuit of the present invention; Figure 7 shows another circuit diagram of a transformer and an LCD screen of a converter circuit of the present invention; Figure 8 shows the LCD power supply of the present invention Detailed circuit diagram of the system; Figure 9 shows another circuit diagram of the transformer and LCD screen in the inverter circuit of the present invention; and Figure 10 shows another CCFL with two controllers and two converters Drive circuit for the driver circuit. [Description of main component symbols] 0, 2 0, 1 0 0 Power supply system 12 Power factor correction circuit 14 Converter] 6 ', 16 DC / AC converter -12- (10) (10) 200426749 18 LCD screen 30, 30, 30 ", 50, 50, 206, 2 08 Converter circuit 3 2, 5 2, 5 2, 2, 2 0, 2 0 4 Converter controllers 34, 36, 54, 56 Switch 38 Transformer 60 The exemplary current feedback circuit 62 Photocoupler 64 Regulator 2 0 0 Drive circuit 2 1 0 Sync signal -13-

Claims (1)

(1) (1)200426749 拾、申請專利範圍 1 · 一種局電壓液晶顯不器電源系統，包括： 一換流器控制器，能控制多數開關，從而把一高電壓 直流信號轉換爲一高電壓交流信號； 多數接收所述高電壓交流信號的變壓器，且每個所述 變壓器都產生一個高電壓正弦信號，其中所述每個變壓器 都有一個一次側和一個二次側，所述每個一次側相互串聯 在該高電壓交流信號的兩端；和 一液晶顯示器螢幕，包括多數冷陰極螢光燈管，每個 所述燈管都由所述變壓器一個對應二次側供電。 2. 根據申請專利範圍第1項所述的電源系統，其中 所述多數開關按全橋式電路結構排列，且所述換流器控制 器能控制所述全橋式電路。 3. 根據申請專利範圍第1項所述的電源系統，其中 所述多數開關按半橋式電路結構排列，且所述換流器控制 器能控制所述半橋式電路。 4 ·根據申請專利範圍第1項所述的電源系統，其中 所述多數開關按Class-D式電路結構排列，且所述換流器 控制器能控制所述Class-D式電路。 5 .根據申請專利範圍第1項所述的電源系統，更包 括產生一個表示供給到至少一所述燈管的電流的電流回授 信號電路，且所述換流器控制器接收所述電流回授信號， 從而調節傳送至所述至少一燈管的電流。 6.根據申請專利範圍第1項所述的電源系統，更包 •14- (2) (2)200426749 括產生一個表示供給到至少一所述燈管的電壓的電壓回授 信號電路，且所述換流器控制器接收所述電壓回授信號， 從而調節傳送至所述至少一燈管的電壓。 7 · —種高電壓液晶顯示器電源系統，包括： 一換流器控制器，能控制多數開關，從而把一個高電 壓直流信號轉換爲一個高電壓交流信號； 多數接收所述高電壓交流信號的變壓器，且每個所述 變壓器都產生一個高電壓正弦信號，所述每個變壓器都有 一個一次側和一個二次側，所述每個一次側均相互串聯於 該高電壓交流信號兩端； 一包括多數冷陰極螢光燈管的液晶顯示器螢幕，每個 所述燈管都由所述變壓器的至少兩個對應二次側供電。 8 ·根據申請專利範圍第7項所述的電源系統，其中 所述燈管連接在一個第一二次側正極和一個第二二次側負 極之間。 9 ·根據申請專利範圍第7項所述的電源系統，其中 所述多數開關按全橋式電路結構排列，且所述換流器控制 器能控制所述全橋式電路。 ]〇 ·根據申請專利範圍第7項所述的電源系統，其中 所述多數開關按半橋式電路結構排列，且所述換流器控制 器能控制所述半橋式電路。 1 1 ·根據申請專利範圍第7項所述的電源系統，其中 所述多數開關按Class-D式電路結構排列，且所述換流器 控制器能控制所述Class-D式電路。 -15- (3) (3)200426749 12.根據申請專利範圍第7項所述的電源系統，更包 括產生一個表示供給到至少一所述燈管的電流的電流回授 信號電路’且所述換流器控制器接收所述電流回授信號， 從而調節傳送至所述至少一個燈管的電流。 1 3 ·根據申請專利範圍第7項所述的電源系統，其中 所述電源系統還包括產生一個表示供給到至少一所述燈管 的電壓的電壓回授信號電路，並且所述換流器控制器接收 所述電壓回授信號，從而調節傳送至所述至少一個燈管的 電壓。 1 4 . 一種用於液晶顯示器的電源系統，包括： 一換流器控制器，能控制多數開關，從而把一直流信 號轉換爲一高電壓交流信號； 多數接收所述高電壓交流信號的變壓器，且每個所述 變壓器都產生一高電壓正弦信號，其中每個所述變壓器都 有一個一次側和一個二次側，所述每個一次側相互串聯在 高電壓交流信號的兩端； 一包括多數冷陰極螢光燈管的液晶顯示器螢幕，所述 多數燈管由所述變壓器的多數二次側供電。 1 5 . —種用於液晶顯示器面板的電源系統，包括： 一換流器控制器，能控制多數開關，從而把一直流信 號轉換爲一高電壓交流信號； 多數接收所述高電壓交流信號的變壓器，且每所述個 變壓器都產生一個高電壓正弦信號，其中每個所述變壓器 都有一個一次側和一個二次側，所述每個一次側相互串聯 -16- (4) (4)200426749 在該高電壓交流信號的兩端； 一包括多數冷陰極螢光燈管的液晶顯示器螢幕，每個 所述燈管都由所述變壓器至少兩個對應的二次側供電。 1 6.根據申請專利範圍第1 5項所述的電源系統，其 中所述燈管連接在一個第一二次側正極和一個第二二次側 負極之間。 1 7 · —種高電壓液晶顯示器電源系統，包括·· 一換流器控制器，能控制多數開關，從而把一直流信 號轉換爲一交流信號的； 多數變壓器二次側，每個所述二次側由所述交流信號 產生一個高電壓正弦信號；和 一包括多數冷陰極螢光燈管的液晶顯示器螢幕，每個 所述燈管都由所述變壓器的一個對應二次側供電。 1 8 .根據申請專利範圍第1 7項所述的電源系統，其 中所述多數開關按全橋式電路結構排列，且所述換流器控 制器能控制所述全橋式電路。 1 9 .根據申請專利範圍第1 7項所述的電源系統，其 中所述多數開關按半橋式電路結構排列，且所述換流器控 制器能控制所述半橋式電路。 20·根據申請專利範圍第1 7項所述的電源系統，其 中所述多數開關按C1 a s s - D式電路結構排列，且所述換流 器控制器能控制所述Class-D式電路。 2 1 ·根據申請專利範圍第1 7項所述的電源系統，更 包括產生一個表示供給到至少一所述燈管的電流的電流回 -17- (5) (5)200426749 授信號電路，且所述換流器控制器接收所述電流回授信 號’從而調節傳輸給所述至少一個燈管的電流。 22 ·根據申請專利範圍第1 7項所述的電源系統，更 包括產生一個表示供給到至少一個所述燈管的電壓的電壓 回授信號電路，且所述換流器控制器接收所述電壓回授信 號’從而調節傳輸給所述至少一個燈管的電壓。 23. —種高電壓液晶顯示器電源系統，包括： 一換流器控制器，能控制多數開關，從而把一個直流 信號轉換爲一個交流信號的； 多數變壓器二次側，每個所述二次側由所述交流信號 產生一個高電壓正弦信號；和 一包括多數冷陰極螢光燈管的液晶顯示器螢幕，每個 所述燈管都由所述變壓器的至少兩個對應二次側供電。 2 4.根據申請專利範圍第23項所述的電源系統，其 中所述燈管連接在一個第一二次側正極和一個第二二次側 負極之間。 25·根據申請專利範圍第23項所述的電源系統，其 中所述多數開關按全橋式電路結構排列，且所述換流器控 制器能控制所述全橋式電路。 2 6 ·根據申請專利範圍第2 3項所述的電源系統，其 中所述多數開關按半橋式電路結構排列，且所述換流器控 制器能控制所述半橋式電路。 2 7 ·根據申請專利範圍第2 3項所述的電源系統，其中 所述多數開關按C 1 a s s - D式電路結構排列，且所述換流器 -18- (6) (6)200426749 控制器能控制所述Cl ass-D式電路。 2 8 ·根據申請專利範圍第2 3項所述的電源系統，更 包括產生一個表示供給到至少一個所述燈管的電流的電流 回授信號電路，並且所述換流器控制器接收所述電流回授 信號，從而調節傳輸給所述至少一個燈管的電流。 2 9.根據申請專利範圍第2 3項所述的電源系統，其中 所述電源系統還包括產生一個表示供給到至少一個所述燈 管的電壓的電壓回授信號電路’並且所述換流器控制器接 收所述電壓回授信號’從而調節傳輸給所述至少一個燈管 的電壓。 -19-(1) (1) 200426749 Patent application scope 1 · A local voltage liquid crystal display power supply system includes: a converter controller that can control most switches to convert a high voltage DC signal into a high voltage AC signals; most of the transformers receiving the high-voltage AC signals, and each of the transformers generates a high-voltage sinusoidal signal, where each transformer has a primary side and a secondary side, and each primary Sides are connected in series with each other at both ends of the high-voltage AC signal; and a liquid crystal display screen including a plurality of cold cathode fluorescent lamp tubes, each of which is powered by a corresponding secondary side of the transformer. 2. The power supply system according to item 1 of the scope of patent application, wherein the plurality of switches are arranged in a full-bridge circuit structure, and the inverter controller can control the full-bridge circuit. 3. The power supply system according to item 1 of the scope of patent application, wherein the majority of switches are arranged in a half-bridge circuit structure, and the inverter controller can control the half-bridge circuit. 4. The power supply system according to item 1 of the scope of patent application, wherein the plurality of switches are arranged in a Class-D type circuit structure, and the inverter controller can control the Class-D type circuit. 5. The power supply system according to item 1 of the scope of patent application, further comprising a current feedback signal circuit for generating a current representing the current supplied to at least one of said lamps, and said inverter controller receives said current feedback A signal to regulate the current delivered to the at least one lamp. 6. According to the power supply system described in item 1 of the scope of the patent application, further including: 14- (2) (2) 200426749 including a voltage feedback signal circuit that generates a voltage indicative of the voltage supplied to at least one of said lamps, and The inverter controller receives the voltage feedback signal, thereby adjusting the voltage transmitted to the at least one lamp tube. 7 · A high-voltage liquid crystal display power system including: a converter controller capable of controlling most switches to convert a high-voltage DC signal into a high-voltage AC signal; and most of the transformers receiving the high-voltage AC signal And each of the transformers generates a high-voltage sinusoidal signal, each of the transformers has a primary side and a secondary side, and each primary side is connected in series with each other at both ends of the high-voltage AC signal; A liquid crystal display screen including a plurality of cold cathode fluorescent lamp tubes, each of which is powered by at least two corresponding secondary sides of the transformer. 8. The power supply system according to item 7 of the scope of patent application, wherein the lamp tube is connected between a first secondary-side positive electrode and a second secondary-side negative electrode. 9. The power supply system according to item 7 of the scope of patent application, wherein the plurality of switches are arranged in a full-bridge circuit structure, and the inverter controller can control the full-bridge circuit. ] 〇 The power supply system according to item 7 of the scope of patent application, wherein the majority of switches are arranged in a half-bridge circuit structure, and the inverter controller can control the half-bridge circuit. 1 1 The power supply system according to item 7 of the scope of patent application, wherein the plurality of switches are arranged in a Class-D type circuit structure, and the inverter controller can control the Class-D type circuit. -15- (3) (3) 200426749 12. The power supply system according to item 7 of the scope of patent application, further comprising a current feedback signal circuit for generating a current indicating the current supplied to at least one of said lamps', and said An inverter controller receives the current feedback signal, thereby adjusting the current delivered to the at least one lamp tube. 1 3 · The power supply system according to item 7 of the scope of patent application, wherein the power supply system further comprises a voltage feedback signal circuit that generates a voltage indicating the voltage supplied to at least one of the lamp tubes, and the inverter controls The voltage regulator receives the voltage feedback signal, thereby adjusting the voltage transmitted to the at least one lamp tube. 14. A power supply system for a liquid crystal display, comprising: a converter controller capable of controlling most switches to convert a direct current signal into a high voltage AC signal; and most of the transformers receiving the high voltage AC signal, And each of the transformers generates a high-voltage sinusoidal signal, wherein each of the transformers has a primary side and a secondary side, and each primary side is connected in series with each other at both ends of the high-voltage AC signal; Liquid crystal display screens for most cold-cathode fluorescent lamps, which are powered by the majority of the secondary side of the transformer. 15. A power supply system for a liquid crystal display panel includes: an inverter controller capable of controlling most switches to convert a direct current signal into a high voltage AC signal; and most of those receiving the high voltage AC signal Transformer, and each said transformer generates a high-voltage sinusoidal signal, wherein each said transformer has a primary side and a secondary side, and each primary side is connected in series with each other -16- (4) (4) 200426749 At both ends of the high-voltage AC signal; a liquid crystal display screen including a plurality of cold cathode fluorescent lamp tubes, each of which is powered by at least two corresponding secondary sides of the transformer. 16. The power supply system according to item 15 of the scope of the patent application, wherein the lamp tube is connected between a first secondary-side positive electrode and a second secondary-side negative electrode. 1 7 · A high voltage liquid crystal display power supply system, including a converter controller that can control most switches to convert a DC signal to an AC signal; the secondary side of most transformers, each of which The secondary side generates a high-voltage sinusoidal signal from the AC signal; and a liquid crystal display screen including a plurality of cold cathode fluorescent lamp tubes, each of which is powered by a corresponding secondary side of the transformer. 18. The power supply system according to item 17 of the scope of patent application, wherein most of the switches are arranged in a full-bridge circuit structure, and the converter controller can control the full-bridge circuit. 19. The power supply system according to item 17 of the scope of the patent application, wherein most of the switches are arranged in a half-bridge circuit structure, and the inverter controller can control the half-bridge circuit. 20. The power supply system according to item 17 of the scope of the patent application, wherein most of the switches are arranged in a C1 a s s-D type circuit structure, and the inverter controller can control the Class-D type circuit. 2 1 · The power supply system according to item 17 of the scope of the patent application, further comprising generating a current return signal representing a current supplied to at least one of said lamps -17- (5) (5) 200426749 signal-signal circuit, and The inverter controller receives the current feedback signal 'to regulate the current transmitted to the at least one lamp tube. 22. The power supply system according to item 17 of the scope of the patent application, further comprising a voltage feedback signal circuit for generating a voltage indicating the voltage supplied to at least one of the lamp tubes, and the inverter controller receives the voltage The feedback signal 'adjusts the voltage transmitted to the at least one lamp. 23. —A high voltage liquid crystal display power supply system comprising: a converter controller capable of controlling most switches to convert a DC signal to an AC signal; the secondary side of most transformers, each of said secondary sides A high-voltage sinusoidal signal is generated from the AC signal; and a liquid crystal display screen including a plurality of cold-cathode fluorescent lamps, each of which is powered by at least two corresponding secondary sides of the transformer. 2 4. The power supply system according to item 23 of the scope of the patent application, wherein the lamp tube is connected between a first secondary-side positive electrode and a second secondary-side negative electrode. 25. The power supply system according to item 23 of the scope of patent application, wherein most of the switches are arranged in a full-bridge circuit structure, and the converter controller can control the full-bridge circuit. 26. The power supply system according to item 23 of the scope of patent application, wherein most of the switches are arranged in a half-bridge circuit structure, and the inverter controller can control the half-bridge circuit. 2 7 · The power supply system according to item 23 of the scope of the patent application, wherein the majority of the switches are arranged in a C 1 ass-D type circuit structure, and the inverter is controlled by (18) (6) (6) 200426749 The device can control the Cl ass-D circuit. 2 8 · The power supply system according to item 23 of the scope of patent application, further comprising a current feedback signal circuit for generating a current representing the current supplied to at least one of said lamps, and said inverter controller receives said The current feedback signal adjusts the current transmitted to the at least one lamp. 2 9. The power supply system according to item 23 of the scope of the patent application, wherein the power supply system further comprises a voltage feedback signal circuit for generating a voltage representing a voltage supplied to at least one of the lamp tubes, and the inverter The controller receives the voltage feedback signal 'to adjust the voltage transmitted to the at least one lamp. -19-
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US7075245B2 (en) 2006-07-11
US8179053B2 (en) 2012-05-15
US7425949B2 (en) 2008-09-16
CN1538793A (en) 2004-10-20
US6936975B2 (en) 2005-08-30
US7550928B2 (en) 2009-06-23
CN100342755C (en) 2007-10-10
US20090039796A1 (en) 2009-02-12
US20040263092A1 (en) 2004-12-30
US20050212790A1 (en) 2005-09-29
TWI242177B (en) 2005-10-21
US20060202635A1 (en) 2006-09-14
US20040207339A1 (en) 2004-10-21
HK1069708A1 (en) 2005-05-27

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